Apparatus for mud weight determination



Feb. 16, 1954 c. R. NICHOLS 2,659,118

APPARATUS FOR MUD WEIGHT DETERMINATION Filed Feb. 19, 1949 Fl 6 INVENTOR.

CHARLES R, NICHOLS ATTORNEYS.

Patented Feb. 16, 1954 ES PATENT OFFICE ArP-ARATUSFOR MUD WEIGHT DEIERMINATION Charles R. Nichols, McAllen, Tex.,-assignor to Sperry-Sun Well Surveying Company, Philadelphia,,Pa'.,'a corporation of Delaware Application February 19, 1949, Serial No. 77,397

, .2 Claims.

This invention relates to a device for autopressure of the formations penetrated. A close control of the density of the drilling mud throughout the drilling operation is generally highly desirable. On the one hand, it is necessary that the weight of the drilling mud be sufficient to provide a hydrostatic pressure adequate to hold back fluids such'as gas or water in the formations encountered in order to prevent a blowout of the borehole. On the otherhand, if the drilling mud becomes too heavy, the drilling fluid may be continuously forced into one or more of the formations penetrated resulting in the condition known as lost circulation. During the course of the drilling frequent adjustment of the weight of the mud, as by the addition of weighting materials, is required to meet the varying conditions encountered. For instance, upon penetration of a gas sand, the mud stream may become considerably lighter due to absorption of gas, in which case it is important 0 that the change in density of the mud fluid be detected immediately so that the proper steps may be taken to increase the weight of the circulating mud and prevent a blowout. In some cases a variation in mud weight of only a small fraction of a pound per gallon may be sufiiciently important to constitute the difference between satisfactory and unsatisfactory drilling progress. It is evident, therefore, that a continual accurate measurement of the mud density during the drilling operation is highly desirable.

Heretofore various devices have been employed in the measurement of density of drilling muds involving various degrees of complication. The principal diificulties encountered in the use of these mud weight indicators arise as a result of plugging or clogging of small lines or ports, jelling of the mud when circulation is arrested or when the mud lies static in parts of the apparatus, and channelling of the mud such as occurs when a portion of the mud in a container jells resulting in a restricted passage through which the mud flows. These characteristics of drilling mud are well known.

It is an object of this invention to provide a 'simple and reliable apparatus for continuously measuring the density of drilling mud.

It is a further object of this invention to provide a simple and reliable apparatus for continuously measuring the density of drilling mud which may be easily assembled by'the drilling crew and which will avoid those diificulties hereinbefore reviewed, namely, plugging, jelling and channelling of the mud. 7 These and other objects of the invention will become apparent from the following description when read in conjunction with the accompanying drawing in which:

Figure 1 is a plan view of the apparatus of the present invention; and- .Figure 2 'is an elevation of the same.

' Referring to the figures, pipe line 2 carries drilling mud, the density of which is to be measured, tothe apparatus and 'pipe line 4 carries the mud away from the apparatus. These two pipe lines are mounted on stands 3 and 5 and are joined in such'a manner by coupling member 6. as to maintaintheir longitudinal axes in alignment. Coupling member '6 includes a central floating members I2 and M, respectively. Members l2 and I4 are identical and a description of the structure of one should be construed as a description of the structure of both. Member [2 is located on pipe 2 so as to position the smaller bore IS in member l2 operably within the periphery of the larger bore IS in pipe 2. It is desirable that bore I8 should be larger than bore IS in order to avoid moments tending to lift or depress pipe 36 such as would result when the peripheries of the two bores are crossed. This would probably occur if the two bores were of equal diameter. Slots 20 and 22 contain 0 rings 24 and 2-6 which bear against the outer wall of pipe 2 providing a bearing between the member l2 and the pipe 2 reducing the friction between the two members. Substantial leakage past the 0 rings is permissible, such leakage serving to further reduce the bearing friction between the two members.

Mounted on pipe line 2 adjacent to the mem member 42.

her I2 are the rings 28 and 30 which are held in position on pipe 2 by set screws 32 and 34. The rings 28 and 30, while allowing member 12 to rotate circumferentially about pipe line 2, prevent the member from sliding longitudinally along the pipe line thus preventing the smaller bore l6 from moving beyond the periphery of the larger bore I8 in a longitudinal direction.

Pipe 36 is mounted in members I2 and t4. While it is shown threaded in position. it could equally well be welded or otherwise satisfactorily attached. Pipe 36, being in the form of a hairpin, is supported at its outermost point, by belt; 38 connected to weighing scales 40-, which in turn, are hung from support structure 42.

It can be readily seen that the. drilling mud passing through pipe line 2 emerges through bore l8, passes through the pipe 36 and is discharged through pipe line 4. By use of the scale 40, which can be adjusted to zero when. the pipe line is empty, the weight of the, mud contained in pipe line 36 can be determined; The weight of the mud and the weight of pipe line 36 will be supported by pipe lines 2 and 4 and support The proportionate division of the load can be calculated and the scales 40 calibrated accordingly so that there may be read on the face of the scales av figuredirectly indicating mud weight in per gallon or in any other desirable units.

Thus, there is provided a simple and practical apparatus which can be readily assembled in the field by the drilling crew for continuously indicating the weight of the drilling mud. All

parts of the apparatus are rugged and fool-proof,

thus facilitating handling in the field, and the apparatus is not susceptible. to plu ging, jelling and channelling of the mud or other similar problems generally encountered in the operation of conventional mud weight apparatus.

What I claim and desire to protect by Letters Patent is: v

1. An apparatus for measuring variations in the density of fluids comprising a first conduit having a first rotatable connection secured thereto, a second conduit in coaxial alignment with said first conduit and having a second rotatable connection secured thereto, each of said connections having an aperture therein adapted. to coincide with an aperture in each of said conduits, a third conduit connecting said rotatable connections and having a portion thereof displaced from the axis of said conduits, and scale means supporting said displaced portion of said third conduit.

2.. An; apparatus. for measuring variations in the density of fluids comprising a first conduit having a first rotatable connection secured adjacent to an. end thereof, a second conduit having a second rotatable connection secured adjacent to an end thereof, means joining and closing ofl said ends of said conduits and retaining said conduits in coaxial alignment, each of said connections having an aperture therein adapted to coincide with an aperture in each of said conduits, a curved conduit connecting said rotatable conmotions, and Scale means supporting said curved conduit intermediate the ends, thereof.

CHARLES R. NICHOLS.

References Cited in the me of this patent UNITED s'ra'rns PATENTS Number Name Date 1,511,6(M Ganucheau Oct. 14, 1924 2,039,997 Hind May 5, 1936 2,400,658 Shepherd May 21, 1 946 2,432,039 Plank Dec. 2, 11947 FOREIGN PATENTS Number Country Date 555,338 Great Britain Aug. 18, 19543 

